This invention relates generally to shipping containers and more particularly to shipping bases, caps, and cartons adapted for handling and stacking by mechanical container handling equipment.
As is well known, an item may be encapsulated for protection against shock and vibration occurring during shipment and handling. It has been conventional to suspend the item in a carton with encapsulating material disposed along top and bottom edges of the item. The encapsulating material serves to both protect the item from vibration as well as to keep foreign objects that may penetrate the carton from contacting the item. As such cartons are often stacked upon each other in a warehouse, the carton and encapsulating material should have sufficient load bearing capability to support multiple items.
One way to solve the problem of adapting such a carton for use with mechanical handling equipment is described in my U.S. Pat. No. 4,610,355 for "Shipping Base Having an Entry Slot for Mechanical Material Handling Equipment", issued Sept. 9, 1986 and assigned to Amana Refrigeration, Inc. That carton includes a shipping base adapted to elevate the bottom of the item in order to provide an entry slot for mechanical handling equipment. The shipping base is formed of cardboard or similar material folded to form a horizontal panel and upward facing rectangular channels disposed along and integrally connected to opposing edges of the horizonal panel. Polystyrene shipping pads are inserted in the channels for physically supporting as well as encapsulating the item. If desired, the item and shipping base may be covered by shrink film or a conventional shipping sleeve open at one end.
While this shipping base works well for most applications, in other applications certain problems have occurred. In particular, if multiple heavy items packaged in the base are arranged in a stack, the stack may tend to lean as time passes. This occurs particularly if the rectangular channels and polystyrene shipping pads are less than adequate for supporting the weight of multiple items in the stack. It may also occur if the various components of the base spread apart, causing it to become dimensionally unstable. Such spreading apart may occur when weight is applied to the base or the base is placed on an uneven surface. Additionally, if the cardboard sleeve is used with stacked items, it may tend to slip or telescope from one item down over an item placed lower in the stack. It then becomes difficult to insert the mechanical handler into the entry slot. When straps are used to hold the sleeve and shipping base together, a flap portion of the sleeve adjacent the fork entry may tend to obstruct the fork entry if the straps loosen. This is a problem particularly when the mechanical handling equipment must be operated amongst package designed with minimal fork entry clearances. It has also been found to be difficult to adapt this shipping base to items having other than a rectangular shape. The cardboard sleeve tends to buckle and/or bow if it is desired to use certain types of squeeze-clamp mechancial handling equipment. Other problems occur in the assembly of the shipping base such as the requirement for a special assembly jig and a tendency for the associated shipping pads to shift or fall out during the packaging process.